Method and device for fighting fires

ABSTRACT

The invention is for a method for firefighting in which a directed jet of extinguisher foam is applied so as to cover the source of the fire, and to a device suitable for implementing this method. The method and device make it possible to extinguish fires which are spreading in area, while at the same time reducing the risk of uncontrolled spread of the fire. According to the invention, this is achieved in that as a supplement to the jet of extinguisher foam, the apparatus discharges individual jets of a mist of firefighting liquid which cools down the space surrounding the source of the fire.

BACKGROUND OF THE INVENTION

The invention relates to a method and a device for firefighting, inwhich a directed jet of extinguisher foam is applied so as to cover thesource of the fire. Furthermore, the invention relates to a device whichis suitable for implementing the method. Such devices are used instationary or mobile firefighting units, to suffocate a fire by means offoam, for example if the use of water as a firefighting liquid is notpossible.

DESCRIPTION OF THE PRIOR ART

A device suitable for firefighting with extinguisher foam is known fromthe British printed patent specification 1 018 431. The device describedin this printed publication comprises a foam tube, a cylindrical sectionof which encompasses a nozzle body. The nozzle body comprises a nozzlethrough which firefighting liquid is applied. To let in the surroundingmedium, the known device has an entry aperture at the rear. In addition,several entry apertures are arranged on the cylindrical circumference ofthe foam tube.

The extinguisher foam generated by means of such a device can be appliedin a directional jet. This provides the advantage that the extinguisherfoam exits at relatively high kinetic energy thus providing considerablereach. The fire can therefore first be fought from a great distance andsubsequently from a lesser distance. At the same time the concentratedapplication of the jet of extinguisher foam causes the foam to impact onthe location of the fire in compact form, forming a thick cover afterimpact, which cover suffocates the fire.

The strong concentration of the jet of extinguisher foam, which isdesirable in view of the ability to cover a long range and achieve goodeffectiveness of the extinguisher foam, is however problematic inpractical applications where fires have to be fought which have spreadacross large areas or which have established themselves in asubstantial, compacted volume such as for example in a stack of wood orpaper. Such fires can be fought by a directional jet of extinguisherfoam only in that the nozzle is moved to and for during firefighting. Asa result of this movement, the jet washes over the surface of the fire,covering it with extinguisher foam after a period of time. Practiceshows however that due to the lack of sealing off of the fire and theincreased ambient temperature, the spread of the fire to adjacentregions and objects cannot always be prevented.

OBJECTS OF THE INVENTION

It is thus the object of the invention to provide a method of the typedescribed in the introduction and a suitable device for carrying outthis method, which make it possible to extinguish fires which arespreading in area, while at the same time reducing the risk of the firespreading.

Concerning the method, this object is met in that as a supplement to thejet of extinguisher foam, a mist of firefighting liquid is dischargedwhich cools down the space surrounding the source of the fire.

SUMMARY OF THE INVENTION

The method according to the invention combines the firefighting methodwhich is known per se for example from the German utility model 295 18911.8, using firefighting mist, with the method of firefighting by meansof an extinguisher foam. It has been shown that the firefighting mistand the jet of extinguisher foam ideally complement each other, inparticular when fighting large-area or large-volume fires. This happensin that as a result of the directional extinguisher jet, the fire isfought directly and the top surface of the fire is gradually covered upwith foam. Furthermore, the firefighting mist cools down the gas spacewhich surrounds the fire. Since the firefighting mist covers asignificantly larger space than does the jet of extinguisher foam, theapplication of the firefighting mist results in a lowering of theambient temperature of the fire also in those regions where directcoverage of the fire by extinguisher foam has not yet taken place, i.e.if the fire in these particular areas is still burning. This preventsthe fire from spreading, for example by spontaneous combustion ofobjects adjacent to the source of the fire, due to the high temperaturesin the surroundings of the fire.

It is particularly advantageous if application of the firefighting mistoptionally depends on the position of a control device. This makes itpossible to match the composition of the firefighting agents(extinguisher foam/mist of firefighting liquid) applied to the region ofthe source of the fire, to the particular fire situation.

The foam tube can be used particularly advantageously in conjunctionwith firefighting appliances where the firefighting liquid is applied athigh pressure, i.e. at pressures above 40 bar.

A further advantageous embodiment of the method according to theinvention is characterized in that a mist of firefighting liquid isapplied in the form of several individual jets whose respective originis in direct proximity to the origin of the jet of extinguisher fluid.Thus it can be ensured in a simple way that most of the mist offirefighting liquid surrounds that section of the fire which iscurrently covered by the jet of extinguisher foam. For this reason, thisembodiment is in particular advantageous in those cases where the methodaccording to the invention is implemented by way of a mobilefirefighting appliance in which the firefighter holds a mobilefirefighting pistol in his/her hand. In this context it is particularlyfavourable if part of the individual jets of the mist of firefightingliquid is directed in the direction of the source of the fire, whileanother part is directed in the perpendicular way, aligned with the axisof the jet of extinguisher foam. In this way, an extended volume ofspace is filled with the mist of the liquid so that it is not only thespace in the immediate vicinity of the fire but also the exhaust gassesrising in the surroundings, that are cooled. It is also favourable if,as a supplement or as an alternative, at least one individual jet isdirected in a direction pointing away from the source of the fire sothat the rear space too, of the firefighting appliance is sure to becovered by the firefighting mist.

Practical trials have shown that the method according to the inventioncan be used particularly effectively if the firefighting liquid fromwhich the mist of firefighting liquid is made, is water.

A device which is particularly suitable for implementing the methodaccording to the invention, said device comprising an extinguishernozzle head which comprises an extinguisher foam generating device forgenerating a directional jet of extinguisher foam, is characterizedaccording to the invention by the extinguisher nozzle head comprisingadditional extinguisher nozzles for generating jets of mist offirefighting liquid. In this, preferably at least one of theextinguisher nozzles can be aligned such that the jet of mist offirefighting liquid emanating from it, is directed in the direction ofthe source of the fire, while at least one further nozzle offirefighting mist is aligned such that the jet of mist of firefightingequipment emanating from it emanates in a direction alignedperpendicularly in relation to the direction of exit of the jet ofextinguisher foam.

Further embodiments of the invention are stated in the dependent claims;in the following description of one embodiment they are explained inmore detail by means of a drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a transportable firefighting pistol L in partiallateral-section view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The extinguisher nozzle head 1 of the transportable firefighting pistolL is constructed so as to be rotation-symmetrical and at its frontcomprises a front surface 2. In the centre of the front surface 2, acentral extinguisher nozzle 3 is arranged. The central extinguishernozzle 3 is connected to a first supply line 4 of the firefightingpistol L, said supply line being routed in the tubular housing R of thefirefighting pistol L.

Shaped to the front surface 2 of the extinguisher nozzle head 1 is arotary bevelled surface 5 which recedes at an angle α of approximately45° in relation to the front surface 2. Extinguisher nozzles 6 arearranged on the bevelled surface 5, said extinguisher nozzles beingconnected to a second supply line 7 of the firefighting pistol L, whichsupply line 7 is also routed inside the tubular housing R. Theextinguisher nozzles 6 are arranged, at regular angular spacings, on acircle which is arranged concentrically to the aperture of the centralextinguisher nozzle 3. The direction of exit of the jet of mistemanating from them if firefighting liquid is applied, is essentially ata right angle to the bevelled surface 5. Consequently, the jets of mistof the extinguisher nozzles 5 are essentially directed in the samedirection as the jet which emanates parallel to the longitudinal axis Xof the extinguisher nozzle head 1 which is generated by the centralextinguisher nozzle 3.

By way of a manually adjustable valve V, firefighting liquid can besupplied to the supply lines 4, 7, either together or individually.Adjacent to the bevelled surface 5 is a radially surrounding casingsurface 8 whose axis extends parallel to the longitudinal axis X of theextinguisher nozzle head 1, with further extinguisher nozzles 9,connected to the supply line 7, being arranged on said casing surface.When firefighting liquid is applied to the extinguisher nozzles 9, theyalso produce a jet of firefighting mist. However, this jet incorporatesa component aligned radially to the longitudinal axis X of theextinguisher nozzle head 1 and a component aligned in the direction ofthe valve V, so that the jets of firefighting mist emanating from theextinguisher nozzles 9 cover the space surrounding the firefightingpistol L rearward and laterally.

On the central extinguisher nozzle 3 a foam tube 11 is attached via asleeve 10. The foam tube 11 comprises a nozzle body 12 with an injectornozzle 13 projecting into the foam tube 11. The borehole 14 of theinjector nozzle 13 is connected to the central extinguisher nozzle 3 viaa chamber of the nozzle body 12 and the sleeve 10. Between the wall ofthe foam tube 11 and the nozzle body 12 there are entry apertures (notshown) through which surrounding air is sucked into the foam tube.

Depending on the position of the valve V, firefighting liquid,preferably water, is supplied to the supply lines 4 or 7, eithertogether or individually. In both supply lines the pressure of thefirefighting liquid is in excess of 40 bar. When applying pressure tothe supply line 4, the extinguisher nozzles 6 and 9 create afirefighting mist where the individual droplets of liquid are of smallvolume and issue from the nozzle openings of the extinguisher nozzles 6,9 into the surroundings finely distributed and at high kinetic energy.The jets of mist emanating from the extinguisher nozzles 6 pointingforward at an angle reach the surroundings of the source of the firewhere by evaporation and by accompanying displacement of the oxygen theycool down the gases that are present there. By contrast, the jetsemanating from the extinguisher nozzles 9 of the casing surface 8 fillthe lateral and rearward space with firefighting mist, so that theretoo, an efficient reduction in temperature is achieved. This not onlyprevents the fire from spreading to the cooled-down area, but at thesame time it also protects firefighting personnel operating thefirefighting pistol.

When pressure is applied to the supply line 7, from the centralextinguisher nozzle 3, a directional jet of firefighting liquid mixedwith a foam-generating additive, is discharged at high pressure from thecentral extinguisher nozzle 3. This jet enters the chamber of the nozzlebody 12 where it is additionally swirled. By way of injector nozzle 13,the jet of firefighting liquid swirled in this way enters the foam tube11 into which it sucks up air via the entry apertures of the foam tube,according to the venturi effect. This air mixes with the fine mist offirefighting liquid, creating a fine-pore foam. This foam emanates fromthe foam tube 11 at high kinetic energy and reaches the source of thefire as a directional, compact jet of extinguisher foam.

The combined action of covering the source of the fire by means of thedirectional jet of extinguisher foam and cooling the space surroundingthe source of the fire by means of the mist of firefighting liquid,considerably reduces the danger of the fire spreading to regions orobjects adjacent to the source of the fire. Likewise, lowering of thesurrounding temperature reduces the exposure of and danger to,firefighting personnel during firefighting.

To carry out the method according to the invention, preferably water isused as a firefighting liquid. Water mist provides advantages as aresult of its excellent thermal binding and inerting properties which,together with the protection from radiated heat which it affords tooperating personnel, increase the effectiveness and usefulness of thefoam generated by the high pressure foam generator located on thecentral jet.

It must be pointed out in particular that the foam tube 11 brings abouta considerable improvement in the reach of the jet of firefighting agentemanating from it, if no foam-generating additive has been admixed tothe firefighting agent, but instead if only the mist of firefightingliquid itself emanates from the foam tube 11 as a jet of high kineticenergy. The use of the foam tube 11 when using liquid without anyfoam-generating additive, is favourable in those cases when for example,a directional jet of firefighting liquid is required to reach the sourceof the fire from a considerable distance. Furthermore, the jet offirefighting liquid concentrated by the foam tube 11, can be used to wethot spots situated deep inside the source of the fire, by applying awell-aimed jet.

What is claimed is:
 1. A method for fighting a fire comprising:directing a jet of extinguisher foam from a firefighting apparatustoward a source of a fire; and in addition to the jet of extinguisherfoam, discharging a mist of firefighting liquid onto a regionsurrounding the source of the fire to cool down this region, whereinsaid mist of firefighting liquid comprises individual jets whoserespective origins on the firefighting apparatus are in direct proximityto the origin of the jet of the extinguisher foam.
 2. The method ofclaim 1, wherein discharging the firefighting mist depends on a positionof a control device on said firefighting apparatus.
 3. The method ofclaim 1 wherein the mist comprises water.
 4. The method of claim 1further comprising directing at least one of the individual jets of themist of the firefighting liquid toward the source of the fire whiledischarging at least one of the individual jets of the mist of thefirefighting liquid in a direction perpendicularly aligned with one axisof the jet of the extinguisher foam.
 5. The method of claim 4 furthercomprising directing at least one of the several individual jets of themist away from the fire.
 6. A firefighting apparatus for fighting a firecomprising: an extinguisher nozzle head with an extinguisher foamgenerating device for generating a jet of extinguisher foam, wherein theextinguisher nozzle head comprises additional extinguisher nozzles forgenerating jets of a mist of a firefighting liquid.
 7. The firefightingapparatus of claim 6 further comprising a valve device, wherein saidvalve device directs the firefighting liquid to at least one of thefirefighting mist nozzles and to the extinguisher foam generatingdevice.
 8. The firefighting apparatus of claim 6, further comprising avalve device, wherein the valve device directs the firefighting liquidto at least one of the firefighting mist nozzles or to the extinguisherfoam generating device.
 9. The firefighting apparatus of claim 6 whereinthe extinguisher nozzles are arranged around the extinguisher foamgenerating device, the extinguisher nozzles being regularly spacedapart.
 10. The firefighting apparatus of claim 9 wherein theextinguisher nozzles are arranged in a circle whose center coincideswith a central axis of the jet extinguisher foam emanating from theextinguisher foam generating device.
 11. The firefighting apparatus ofclaim 6 wherein at least one of the additional extinguisher nozzles ispositioned such that its jet of the firefighting liquid is directedtoward the source of the fire and at least one further additionalextinguisher nozzle of the firefighting liquid is positioned such thatits jet of the mist of the firefighting liquid is directedperpendicularly to the direction of exit of the jet of the extinguisherfoam.
 12. The firefighting apparatus of claim 11 wherein theextinguisher nozzle head comprises: a radially surrounding casingsurface; and a bevelled surface arranged between an essentially planefront surface and the radially surrounding casing surface, said bevelledsurface tapering from the radially surrounding casing surface towardsthe essentially plane front surface wherein several extinguisher nozzlesare arranged on the radially surrounding casing surface and the bevelledsurface.